1. Field
The disclosed concept relates generally to electrical switching apparatus and, more particularly, to electrical switching apparatus such as, for example, circuit breakers. The disclosed concept also relates to shunt separators for electrical switching apparatus.
2. Background Information
Electrical switching apparatus, such as circuit breakers, provide protection for electrical systems from electrical fault conditions such as, for example, current overloads, short circuits, abnormal voltage and other fault conditions. Typically, circuit breakers include an operating mechanism which opens separable contacts to interrupt the flow of current through the conductors of an electrical system in response to such fault conditions.
The separable contacts generally include a movable contact, which is disposed on a movable contact arm or finger, and a corresponding stationary contact. The movable contact arm is pivotable to move the movable contact into and out of electrical contact with the corresponding stationary contact. For example, the circuit breaker includes an operating assembly having a trip bar. The operating assembly cooperates with the movable contact arm to trip open the separable contacts in response to a fault condition.
The circuit breaker also includes a trip assembly having a load conductor and a plurality of flexible conductors (e.g., without limitation, wires; braids; cables), commonly referred to as shunts. The shunts electrically connect the movable contact arm and the load conductor. More specifically, each shunt is electrically coupled at one end to the load conductor, and at the other end to the movable contact arm. Typically, there are two shunts for each movable contact arm, with each shunt extending past a corresponding portion of the trip bar and being electrically connected to a corresponding end of the movable contact arm. The shunts are flexible to accommodate the motion of the movable contact arm during a fault condition. However, during short circuit fault conditions, for example, magnetic forces cause the two flexible shunts to attract one another. As a result, the shunts move and have a tendency to compress against the corresponding portion of the trip bar. Additionally, an arc, which results from the short circuit, generates debris and particulate matter that can accumulate on the trip bar and/or shunts. These occurrences undesirably inhibit operation (e.g., pivoting) of the trip bar and, therefore, can cause or contribute to adverse interrupting performance (e.g., without limitation, a no latch condition) of the circuit breaker.
There is, therefore, room for improvement in electrical switching apparatus such as, for example, circuit breakers and in shunt separators therefor.